The Blood Brothers were large twin ape-like aliens originally in the service of the conqueror Thanos, acting as the guardians of his first base on Earth. Pursued by Drax the Destroyer, the duo battled the superheroes Iron Man and the Thing in a bid to stop them from interfering in Thanos' plans. When they failed to do so, a disgusted Thanos teleported the Blood Brothers away. The Blood Brothers were imprisoned, but were later released by the hero Quasar and left on the planet Mars.